I am married as well - my husband brought into our relationship a straight female - i am bi - and was rejected by her.
It is difficult to see your spouse being pleased emotionally intellectually sexually by someone else - it is painful to stand by and often feel like am I not good enough?
But I became accepting of this relationship though it ultimately ended because there was so much drama and too much competition. Perhaps you should give your wife time and sit down with her to see what she is comfortable with?
It is very difficult for a wife who is mono trained to try to live the poly life - as I know from experience.
Good Luck to you friend! I wish you nothing but happiness and love!